It has long been felt that there exists a need for an extremely simple, economical and reliable single-turn potentiometer. One recent development in this search has resulted in the use of a shortened helical spring to form the wiper portion of a rotor assembly. The helical spring replaces earlier wipers of the plural finger type. This recent design included the use of a recess in the rotor for insertion of an element formed of resilient material such as solid silicone rubber as a backing for the helical spring. The resilient element essentially embraces and presses against the rear portion of the coiled spring wiper which is held in the recess of the rotor. Thus when the rotor rotates, the resilient element helps the wiper roll and slide along the surface of the resistance element. The individual coil sections of the spring effect multiple electrical contact with the resistance element. In this construction, a rather short coil spring was employed to enhance the smooth sliding of the wiper so as to provide optimum mechanical and electrical characteristics of the potentiometer.
In spite of the improvement in using a coil spring wiper, problems still existed prior to the present invention in providing reduced contact resistance variation (CRV) and improved torque control. Problems also existed prior to the present invention in providing reliable electrical connections to the substrate element.